Validity
Nothing to with VFR. It is to do with MEP(land) versus SEP(land).
Whopity has identified that to undertake training at a FTO you should have a valid licence and rating. Worth checking.
For the SEP Renewal Test it is unlikely that you will be required to undertake any nav as you are currently flying, as you say, on the Multi-engine/IR course. No point to it, the Nav is the bit on which the examiner has discretion.